About half the money, give or take, is for above the line talent. So you have your actors, directors, producers, ect. They get paid in a percentage or in absurdly high amounts for films.
These people are also accommodate on set so production has to rent out luxury campers to house them for weeks or months at a time when on location.
Then they need to hire drivers and trucks to move those campers. Top tier stars can make demands on top of that.
I saw Jim Carrey’s camper once and it had an entire astroturf lawn on top of it, with a picnic table, with a vase with flowers on it. Don’t ask me why he wanted it, he just did.